Clinical management of asthma and COPD is complex, largely because of the marked heterogeneity observed in these conditions. Phenotyping is a new approach that can assist clinicians. This review seeks to describe an approach to clinical and inflammatory/molecular phenotyping of asthma and COPD. Clinical phenotypes can be considered in the key domain areas of comorbidity, airway, and risk factors. Evidence-based therapy can be linked to each of the components of these airway disease phenotypes. The concept can be extended to identify disease endotypes, where a pathogenic mechanism is linked to a specific treatment, and biomarkers are used to identify endotypes. Eosinophilic inflammation is perhaps the best characterized endotype of airway disease. Molecular endotypes are now also being identified using transcriptomic approaches. Phenotyping asthma and COPD represents a new and potentially effective approach to the management of these heterogeneous airway diseases. (BRN Rev. 2016;2:239-52)